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https://issues.apache.org/jira/browse/FLINK-1319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14568988#comment-14568988
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ASF GitHub Bot commented on FLINK-1319:
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Github user rmetzger commented on the pull request:

    https://github.com/apache/flink/pull/729#issuecomment-107924813
  
    I understand that concern.
    
    But using sysoutput will also be interleaved with the Client sysout 
printing and the regular system logging.
    Also, I think its very bad practice to print stuff using systemout, because 
its not controllable in any way.
    With log4j we can configure the analysis output the way we want.
    if you want the messages to look like regular sysout text, we can specify a 
custom output schema for the classes in the sca java package.


> Add static code analysis for UDFs
> ---------------------------------
>
>                 Key: FLINK-1319
>                 URL: https://issues.apache.org/jira/browse/FLINK-1319
>             Project: Flink
>          Issue Type: New Feature
>          Components: Java API, Scala API
>            Reporter: Stephan Ewen
>            Assignee: Timo Walther
>            Priority: Minor
>
> Flink's Optimizer takes information that tells it for UDFs which fields of 
> the input elements are accessed, modified, or frwarded/copied. This 
> information frequently helps to reuse partitionings, sorts, etc. It may speed 
> up programs significantly, as it can frequently eliminate sorts and shuffles, 
> which are costly.
> Right now, users can add lightweight annotations to UDFs to provide this 
> information (such as adding {{@ConstandFields("0->3, 1, 2->1")}}.
> We worked with static code analysis of UDFs before, to determine this 
> information automatically. This is an incredible feature, as it "magically" 
> makes programs faster.
> For record-at-a-time operations (Map, Reduce, FlatMap, Join, Cross), this 
> works surprisingly well in many cases. We used the "Soot" toolkit for the 
> static code analysis. Unfortunately, Soot is LGPL licensed and thus we did 
> not include any of the code so far.
> I propose to add this functionality to Flink, in the form of a drop-in 
> addition, to work around the LGPL incompatibility with ALS 2.0. Users could 
> simply download a special "flink-code-analysis.jar" and drop it into the 
> "lib" folder to enable this functionality. We may even add a script to 
> "tools" that downloads that library automatically into the lib folder. This 
> should be legally fine, since we do not redistribute LGPL code and only 
> dynamically link it (the incompatibility with ASL 2.0 is mainly in the 
> patentability, if I remember correctly).
> Prior work on this has been done by [~aljoscha] and [~skunert], which could 
> provide a code base to start with.
> *Appendix*
> Hompage to Soot static analysis toolkit: http://www.sable.mcgill.ca/soot/
> Papers on static analysis and for optimization: 
> http://stratosphere.eu/assets/papers/EnablingOperatorReorderingSCA_12.pdf and 
> http://stratosphere.eu/assets/papers/openingTheBlackBoxes_12.pdf
> Quick introduction to the Optimizer: 
> http://stratosphere.eu/assets/papers/2014-VLDBJ_Stratosphere_Overview.pdf 
> (Section 6)
> Optimizer for Iterations: 
> http://stratosphere.eu/assets/papers/spinningFastIterativeDataFlows_12.pdf 
> (Sections 4.3 and 5.3)



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